Solid electrolytic capacitor for high voltage environments

Abstract

A capacitor element for use in high voltage environments is provided. More particularly, the capacitor element contains an anode that includes a solid electrolyte that overlies an anode. The anode includes a sintered porous pellet and a dielectric layer having a reduced degree of crystallinity formed on a surface of the pellet and within its pores.

What is claimed is: 
     
       1. A method of forming a high voltage solid electrolytic capacitor element, the method comprising:
 subjecting a sintered anode pellet to a formation profile to form an anode, wherein the formation profile includes subjecting the pellet to an increasing current so that a target forming voltage is achieved in about 30 minutes or less; and 
 applying a solid electrolyte to the anode. 
 
     
     
       2. The method of  claim 1 , wherein the current is increased to a peak current, which is reached in about 30 minutes or less. 
     
     
       3. The method of  claim 2 , wherein the peak current ranges from about 1,000 to about 6,000 milliamps. 
     
     
       4. The method of  claim 1 , wherein the target forming voltage ranges from about 100 to about 500 volts. 
     
     
       5. The method of  claim 1 , wherein the formation profile further includes decreasing the current after the target forming voltage is achieved. 
     
     
       6. The method of  claim 5 , wherein the current is decreased at a non-linear rate. 
     
     
       7. The method of  claim 5 , wherein the target forming voltage is held at a relatively constant level as the current is decreased. 
     
     
       8. The method of  claim 7 , wherein the target forming voltage is held relatively constant for a period of time ranging from about 20 minutes to about 300 minutes. 
     
     
       9. The method of  claim 1 , wherein the solid electrolyte includes a conductive polymer. 
     
     
       10. The method of  claim 1 , wherein the solid electrolyte is formed by a process that includes applying a dispersion of conductive polymer particles to the anode. 
     
     
       11. The method of  claim 10 , wherein the conductive polymer particles include a substituted polythiophene. 
     
     
       12. The method of  claim 11 , wherein the conductive polymer particles have an average diameter of from about 1 to about 200 nanometers. 
     
     
       13. The method of  claim 1 , wherein the pellet is dipped into an electrolyte and thereafter subjected to the formation profile.